Ten more doctor groups, including five of the largest in the Cincinnati area and two large Dayton medical practices, have joined the Independent Physicians Collaborative.

The goal is to boost brand recognition and marketing to patients, insurance companies and large employers. The collaborative hopes to persuade employers to make sure the doctor groups are among the medical providers in networks designated by health insurance plans.

Imagine you’re a Medicare patient, and you go to your doctor for an ultrasound of your heart one month. Medicare pays your doctor’s office $189, and you pay about 20 percent of that bill as a co-payment.

Then, the next month, your doctor’s practice has been bought by the local hospital. You go to the same building and get the same test from the same doctor, but suddenly the price has shot up to $453, as has your share of the bill.

Some of the largest physician groups in Greater Cincinnati have formed a collaborative to boost brand recognition and marketing to patients, insurance companies and large employers such as General Electric, Kroger and Macy’s.